Method of operating electric motors, generators, and other apparatus.



Non 642,966. PATENT@ FEB: 5y 1907. R. D. MBRSHGN, Y METHOD 0F @Hmmm ELEGTMG MGTORS5 GENBRATQRS, Mm OTHER APARAUS.

APHJIOAMON FILED m31, m04.

No. 842,966. PATENTED FEB. 5, 1907. R. D. MERSHON. METHOD OF OPERATING ELECTRIC MOTORS, GENERATORS, AND OTHER APPARATUS.

APPLICATION FILED 113.1. 1904,

3 SHEETS-SHEET 2.

W Inl/anim' Winesses:

Y PATENTED FEB. 5, 1907.

l R. DIMERSHON. METHOD 0F OPERATING ELECTRIC-MOTORS, GENERATORS, AND OTHER' APPARATUS.

JIPPLIOATVION FILED mm1. 1904.

s SHEETS-annu a.l

nesses.- Ea/M//f y@ @wap/Aff YUNITED STATES RALPH D. MERSHGN, OF NEv YORK, N. Y.

PATENT OFFICE.

Specification of Letters Patent.

atented Feb. 5, 190'?.

Application filed February Il., 1904. Serial No. 191,464.

To all whom, it ntayctnzccrnf:

Be it known that I, RALPH D. Mnnsnox, a citizen of the United States, residing at New York, in the county and State of Xew York, have invented a certain new and' useful Method'of Operating Electric Motors, Generators, and other Apparatus, of which the following is a specifica-tion, reference being had to the drawings accompanying and forming part lof the same.

The invention which forms the subject of the present application for Letters Patent relates more particularly to the obtaining of any desired speed in motors and any desired frequency in generators, whether of the induction or synchronous type, though the invention is applicable as well to other apparatus in which magnetic poles are produced, as will appear more clearly from the detailed explanation given hereinafter; nor is ,the application of the invention .limited to any particular type of apparatus, whether single phase or polyphase, or to any particular kind of windings, Whether Gramme ring or drum, uniformly or non-uniformly distributed, dce.; but it applies to any winding which will lend itself to the production of the desired angle between poles. For the sake of convenience and brevity, however, the description of the invention will be confined to the case of its application to a single-phase induction inachine with a uniform ring-winding.

lt is usual in alternating-current apparatus to consider that the speed or the frequency dependsupon t-he number of poles in the exciting or energizing element and that a closed or complete system of poles must be used,

and heretofore, so far as l am aware, only an even number of polesthat is, two or a multipie of two-and a closed system of poles have been considered in this connection. Hence the obtaining of different speeds and frequencies by variation of the number of poles, either by change in the design of the apparatus or by changing the points of connection or otherwise changing the connections in any way when the construction o f the apparatupermits such manipulation. is confined to closed systems of poles and to speeds or frequencies corresponding to pole numbers differing by at least two. This difference may sometimes be greater than is desirable. F or example, a motor having four poles operated by currents having a frequency of three thousand six hundred alternations per minute will have a synchronous speed of nine hunored. If the number of poles be 1ncreased to six, the synchronous speed will then be six hundred, and if the number be reduced to two,v the synchronous speed will be eighteen hundred. The difference in the two cases is three hundred and nine hundred, respectnfely, and it may often happen that t-hese variations are too large for the purposes intended. It is therefore desirable to have some method by which'practically any difference may be obtained, thereby securing a more convenient control of speed or frequency. reduce the number of leads to the apparatus even for speeds or frequencies corresponding to an even number of poles and which would therefore admit of a closed system of poles. This is especially the case with some forms of windings which are inherently such that the production of certain even pole numbers would greatly multiply the number of leads to the apparatus.

To provide a method which will accomplish these results is the obj ect of my present invention.

The same consists in the novel method hereinafter described, and more particularly set forth in the claims.

' it will be more easily understood when eX- plainedin connection with the accompanying dra-wings, in which- Figure l represents diagrannnatically a uniformly-distributed gramme-ring winding and the connections for sixteen poles. Figs. 2 and 3 show the same element, but with some of the connections, and consequently the corresponding poles, omitted, the remaining connections and poles being as before. Fig. e shows a similar winding, with the equivalent of two poles, and Fig. wit-h the equivalentof three poles, so far as'speed or frequency 1s concerned. Fig. 6 shows another arrangement for the equivalent of two and two-thirds poles, giving'a cor esponding speed or frequency. Fig. 7 shows an arrangement for the equivalent of nine poles, and Fig. S another arrangement for the same purpose. Fig. 9 is a diagram showing a ring-winding differing in t-he manner of the connections of its coils from that of the pre'- vious figures and giving an equivalent of twelve and one-half poles. Here the connections are for convenience of illustration shown brought out to a system of contacts in a manner somewhat similar to that in which the leads from a direct-current armature are It may also at times be desirable to IOO IIO

brought out to the commutator-segments The arrows applied to the contacts show the direction of the currentslsupplied to the-winding and the points at which they enter the saine. The arrows around the circumference of the ring show the directions of the magnetizing forces in the coils to which 'they correspond, due to the currents in the coils. If the ring shown be, say, the primary of-an induetion-motor, the seoondarymay b'e consideredA as outside of the ring, or if the'Sec'Ondary be considered as inside' the ring thevarious leads inside lthe ring would be considered as re moved tothe outsideoras displaced a suin- Acient distance from Athe planeofthe figure.`

Figs. 10 and 11 show the relative positions of the poles in apparatus withfour. and sixV poles', respectively. Fig. 12 shows 'in ldia-- whole of the circumference, the result being y an open system of poles in each case. l

Referring now to Figs. 1 and 2, it will be seen that the latter is the same'as the former,

with the exception that six poles are omitted.l

N evertheless,-the angles between the remaining oles are the same, and therefore the sync onous speeds or frequencies are the same.

the fields of poles7`8 9 10 11 and`15 16.1 2 3 will be affected with the same frequency Whether it be moving in Fig. 1 or in Fig. 2. Conversely, with the same frequency in each example the synchronous'speed would be the same in both cases. It therefore follows, as previouslystated, that the angle between the poles is the determining factor of synchronous speed or of frequency. If the principles be applied to the ordinary form of generators and motors of the synchronous type, whether the poles are salient ornot, but in which, in general, the coils of the otherelement embrace angles approximatelyY that of the pole-pitch, there will be. a tendency for poles to ybe induced by the currents inthe other element at the pointswhere excitation is suppressed, and such induction will result unless the iield structure be suppressed at these points, but whether the latter be `suppressed'or not and if the poles be induced thetype, in which the circuits of the other ele- `ment embrace angles in general considerably This vfollows from the fact that a" con; ductor moving'with the same speed through In structures of the induction' less than the polar pitch, this inductive eii'ect will extend only slightly beyond the excited portion ofthe exciting'element. If the circuits of the other element embrace angles approximately equal to the polar pitch, this inductive effect may, as in the previous case, extend beyond'these poles, but, as previously stated, in such case the principle of myinvention is in no way invalidated. Bearing in mindjthemthat the speed or frequency dependsuponthe angular s acing of the poles 'the apparatus shovvn'in 4ig. 4 will have a 'synchronous speed or frequency corresponding to twopolesybut in Fig. 5, Wherethe leads yare-one lhundred and twenty degrees apart, the synchronous `speed or frequency corresponds to` three poles. Similarly in Fig. 6, when the leads are spaced 'so asto bring 135o apart the synchronous speed or yfrequency corresponds to two and twothirds poles. Fig. 7 shows connections for nine'poles by spacing Ithe p'ol'es forty degrees apart. It will be n'oticed that withy an odd or non-integral number of poles two 'poles ofthe same sign fall adjacent to eachother. When their proximity becomes'such that they ywill in anyway interfere, either in the exciting-Windingor in the poles of opposite sign winding. of the other element, as many poles,

: ber of coils is used, which of it self prevents the use ofan integral number of poles, and therefore the' use of'a closed' system of poles, since one of theconditions fora closed system of poles is'that'the number of poles shall be an even integer. There is another reason aside lfrom"that of` the odd number of coils why Fig. 9 would'not vadmit of a closed system of poles for certain pole numbers, although it might-for others if it had an'even number of coils divisible by the'number of poles required An examination of Fig. 9 will show that coils approximately -opposite will, if the proper` terminals be chosen, be in.- series.

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This means that the relationbetween the poles 4the number of coils were even, such poles mightbe exactly opposite. Now the condition of poles of the'same sign at opposlte ends of a diameter 1s one which answers for contrary sign.

saar-tee some numbers of poles, but not for others, as Will be seen on comparing Figs. 'l0 and il, representing apparatus similar to that already described, Fig. 1.0 showing a four-pole connection and Fig. 11 one for six poles. In the former poles of the saine sign come opposite; but in the latter opposite poles are of It Will be evident, therefore, that in a Winding similar to that of 9, even if the number of coils be such as is evenly divisible by an even number of poles, (in which case, therefore, with a Winding connected similarly'to Fig. 9 poles of the same sign Will come exactly opposite instead of approximately opposite, as in Fig. 9,) it,

'will be impossible to obtain pole-numbers other than those in which poles of the same sign are opposite unless opposite coils be used in other than their series connection, which will necessitate a greater number of leads to the apparatus. In such a Winding, therefore, in order to keep down the number of leads itl might at times be desirable to use the opposite coils in their series connection, and in order to do so for pole-numbers other than those in Which poles of the'same sign come opposite it would be necessary to operate with the poles in two or more groups, as in Fig. 9, the groups being separated by an unexcited portion of t-he element- This ex lanation, 'which has been made with re erence to a Winding in which the coils connected in series are opposite or approximately opposite, holds for the series connection of coils bearing any other definite fixed rel ation--as, for inst ance, where the coils are arranged at intervals of ninety degrees.

In Fig. 12 is showna system, which` for the sake of simplicity, inthe diagramis shown 'as for single phase. and with a uniformlydistributed ring-Winding, adapted for cha-nge in the number of its poles by change in the points at Which the current or currents are led into the Winding. By tracing out the connections itl Will be seen that in the first position of the controller (diagrammatic-ally indicated at C) current will be supplied to the motor by leads 1-4-6-9-12-14, each sixty degrees apart, and therefore producing six poles. In the next position leads 2-5-8 of one group are fifty-one and three-sevenths degrees apart, and leads 10-13--16 of another group are also titty-one and three-sevenths degrees apart, thus giving a speed equivalent to seven poles. current is fed through leads 1-3-5-7-9-11- 13-15, which are forty-five degrees apart., giving eight. poles.

speed, corresponding to seven poles, by omit.- ting one lead from the possible total of seven In the next position the In the intermediate;

leads and arranging the two groups of three i each With the middle lead of each group on a diameter the total number of leads is reduced, since by so arranging them noty only has the one lead mentioned been omitted,

butJ ithas also been made possible to use leads 5 and 13, which are employed in the eight-pole connection. The same principles apply, of course, to polyphase apparatus rand to windings other than the ring form, or those which are uniformly'distributed.

The novel appara-tus described herein I do noty claim in this application, but do vso broadly in my copending application, filed December 3, 1906, Serial No. 346,094.

. TWhat I claim is- 1. The method of obtaining a desi'red speed or frequency in apparatus in which magnetic poles are' produced, which consists in producing the poles in separated groups in which angular distances between adjacent poles of opposite sign in the saine group correspond to the speed or frequency desired, as setforth.

2. The method of obtaining a desired speed or frequency in apparatus in which magnetic poles are produced, equivalent to an odd or non-integral number ot poles, which consists in producing the poles with angular distances, between adjacent poles of opposite sign, corresponding to the desired speed or frequency.

3. rlhe method of obtaining a desired speed or frequency in apparatus in which magnetic poles are produced, equivalent to an odd or 9 non-integral number of poles, which consists in producing the poles with angular distances, between adjacent poles of opposite sign, corresponding to the desired speed or frequency, and Where a continuation of such production of poles around the circumference of the excited element causes overlapping or interference of poles, dropping out one or more poles at such point.

4, The method of obtaining a desired speed or frequency'in apparatus in which magnetic poles are produced, equivalent to an odd or non-integral number of poles, which consists in producing the poles in groups with angular distances, between adjacent poles of opposi-te sign in the same group, corresponding to the desired speed or frequency.

5. The method of obtaining a desired speed or frequent?)v -in apparatus in which magnetic poles are produced, equivalent to an odd or non-integral number of poles, which consists in producing the poles in separated groups, with angular distances between adjacent poles of' opposite sign in the same group, corresponding to the desired speed or frequency.

6. In electrical apparatus in which magnetic poles are produc-ed,and which is adapted for change of the number of poles therein, the method of varying the speed or the frequency which consists in changing the number of poles and producing the same in separated groups in which angular distances, bc-

tiveen adjacent poles ot' opposite sign, cru-respond to the speed or frequency desired, as set forth,

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7. In electricalA apparatus in which magnetic poles are produced, and which is adapted for change of the number of poles therein, the method of varying the' speed or frequency and obtaininga speed or frequency equivalent to an odd or non-integral number .of pole-s, which consists in producing the poles with angular distances, between adjacent poles of opposite sign, corresponding to the desired speed or frequency, as set forth.

8. In electrical apparatus in which inagnetic poles are produced,- and which is adaptedforchange of the number of poles therein, themethod of Varying the speed or frequency and obtaining a speed or frequency equivalent to an'odd cr non-integral number of poles, which consists in producingv .the poles with angular distances, between adjacent poles of opposite sign, corresponding to the desired speed or frequency, andI Wherea continuation of such production of poles around the circumference of the excited element causes overlapping orinterference of poles, dropping out one or. more poles at such point, as set forth.

9. In electrical apparatu-s in which magj netic poles are produced, and which is adapted for change of the number of poles therein, the method of Varying the speed or frequency and obtaining a speed or frequency equivalent` to an odd or non-integral number of poles, which-consists in producing the poles4 1n groups with angular distances, between adjacent poles of opposite sign in the same group, corresponding to the desired speed or frequency, as set forth.

10. In electrical apparatus in which magnetic poles are produced, and which is adapted for change of the number of poles therein, the method of Varying the speed or frequency and obtaining that equivalentv to an odd or non-integral number of poles, whichconsists in producing the poles in separated groups with angular distances, between adjacent poles of opposite signin the same group, corresponding to the desired speed or frequency, .as set forth.

11. In electrical apparatus in which magnetic poles are produced, the methodof obtaining a speed or frequency'equivalent to an odd Aor non-integral number of poles, which consists in feeding the current or currents into the winding at such oints as will pro-, duce poles with angular fistances, between adjacent poles of opposite sign, correspondingto the desired speed or frequency, as set forth.

12. In electrical apparatus in which inagnetic poles are produced, the method of ohtaining a speed or frequency equivalent to an odd or non-integral number of poles, which consists in feeding the current or currents into the winding at. such points as will produce poles with angular distances, between adjacent poles of opposite sign, correspondses, eee

ing to the desired speed or frequency, and where such production of poles around the circumference of the excited element` will cause overlapping or interference of poles, dropping out one or more poles at such point, as set forth.

13. In electrical apparatus in which magnetic poles are produced., the method of obtaining a desired speed or frequency which consists in feeding the current or currents into the winding at such points as will produce the poles in groups with angular distances, between adjacent poles of opposite sign in the same group, corresponding.l to the' desired speed or frequency, as set forth.

14. In electrical apparatus in which mag'- netic poles are produced, the method of obtaining a speed or frequency equivalent to an odd or non-integral number of poles, which consists in feeding the current or currents into the winding at such points as will produce the poles in separated groups with angular distances, between adjacent poles of opposite sign in the same group, corresponding to the desired speed or frequency, asset forth.

15. In an alternating-current motor, the method of obtaining a desired speed, equivalent to an odd-or non-integral number of poles,

which consists in feeding the current or currents into the winding at such points as will produce poles with angular distances, between adjacent poles of opposite sign, corresponding to the speed or frequency desired, as set forth.

16. In an alternating-current motor, the method of obtaining a desired speed, equivalent to an odd or non-integral number of poles, which consists in feeding the current or currents into the winding at such points as will produce poles with angular distances, between adjacent poles of opposite sign, corresponding to the desired speed or frequency, and where such production of poles around the circumference of the excited element will cause overlapping or interference of poles, dropping out one or more poles at such point, as set forth.

17. In an alternating-current motor, the methodof obtaining a desired speed, vwhich consists in feeding the current or currents into the winding at such points as will produce the poles in groups with angular distances, between adjacent poles of opposite sign in the saine group, corresponding to the desired speed, as set forth.

18. In an alternating-current motor, the niethod of obtaining a speed equivalent to an odd or non-integral number of poles, which consists in feeding the current or currents into the winding' at such points as will produce the poles in separated groups with angular distances, between adjacent'-poles of opposite sign in the same group, corresponding to the speed desired, as set forth.

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19. In an alternating-current motor adapted for change of the number of poles therein,-

the method of varying the speed Jfrom that corresponding to a given angle between poles to a speed equivalent to an oddl or non-integral number of poles, Which consists in changing the angle between adjacent poles of opposite sign to that corresponding to the desired speed, as set forth..

20.. In an electrica apparatus in which magnetic poles are produced, the method of obtaining a desired speed or frequency inter* 

